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Noisy one pipe steam system in Pittsburgh

My wife and I are new to our 1950's house, and are learning to coexist with our one pipe steam system.  The previous owners were a little lazy about home maintenance, but a new boiler was installed in 2003 and seems to be in good condition.   

We have taken a few steps to balance the system and quiet the knocking and whistling.  We changed several of the old malfunctioning vents with new Gorton's, insulated the majority of the exposed pipes in the basement, drained the majority of the gunk from the boiler, pitched the radiators, and lowered the pressure to 1 1/2. 

This has helped some, but the noises still persist, especially the whistling.  Also, one of the second floor radiators gurgles like a dishwasher once the system gets going. 

I feel like we're working with "wet steam" and have included a couple of pictures of the near-boiler piping for those more knowledgeable than I.

Any suggestions about self-fixes, or recommendations for knowledgeable professionals in the Pittsburgh area would be great.

Thanks for the help!


  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,612
    edited December 2009
    Wet steam

    The only obvious things is the bell reducer coming out the top of the boiler.  I would have stayed three inch until the take-off and equalizer; it slows down the steam and lets it shed water.  That may not be the source of your troubles though.

    Other than the pipe size and the use of malleable fittings (they should have been cast iron, but I'm being picky), the piping looks fine.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hourTwo btu/ per sq ft for degree difference for a slab
  • Steam in Pittsburgh

    Hi - From the pictures you provided your boiler piping looks reasonable. It would have been better if they had sized the header piping to the size of the boiler exit taping. The header pipe should slope towards towards the equalizer,you might want to check that. You also might want to insulate the header piping and the riser going from the header to the mains. I finally did this after several years without and it made a big difference. 

    The "hissing" sounds like either too much pressure and /or a main venting problem. Let's look at the main vents first - How are your main vents? Have they been replaced recently?  As for the possible wet steam, does the waterline in your sight glass bounce a lot? (3 /4 of an inch is about normal)

    - Rod
  • Dave-o
    Dave-o Member Posts: 9
    main vent

    Thanks for the responses. 

    As far as I can tell the main vent is original to the system, and is probably due to be replaced (see image below). 

    The water in the sight glass only jumps a little, within 3/4" range.  One other thought is that the system probably hasn't been flushed since it's install in 2003, if even then.  Could the system be gunked up and blocking steam/condensate flow?

    I'll finish insulating the pipes, to help the steam stay steam.

    Thanks again.
  • Main Vents

    The vent in the picture looks like an old Dole vent and I agree with you, it probably needs to be replaced.  The idea is to have the air vent rapidly from the Main use large capacity vents so that the steam gets quickly to the radiators. The radiator vent then just has to vent its own radiator.  The "hissing" you are now hearing is probably because the radiator vent is now venting both the radiator AND the main.

    If you let us know the size of the main,diameter and length we can calculate what size vent you need. Most popular main vents seems to be either a Gorton #1 or a Gorton #2. The Gorton #2 has 3 times the venting capacity of a Gorton #1.  Pex Supply http://www.pexsupply.com/  has Gorton, You can get more information there.

    Flushing you boiler- It's a good idea to flush your boiler regularly. I flush mine in the spring at the end of the heating season and again in the fall when the season starts again. It's agood idea to also flush your wet return as most of the "crud" settles there.  When you add new water to your boiler you want tpo be sure to bring the boiler water to where it makes steam as this drives off excess oxygen which can be very corrosive to your boiler.

    If you don't have a copy already I'd suggest you get a book available on the website called "We Got Steam Heat"   It's written for the homeowner, is easy humorous reading and in an evening or two  you'll know a lot more about yoor steam system. Here's a link:


    - Rod
  • mchema
    mchema Member Posts: 37
    Same issues

    My husband and I our experiencing the same issues. We did all of the things you did, we even increased our main vents. Which truth be told unveiled a new crop of new issues.  Finally after "Dealing" with our heat I took it upon ourselves to find a good steam specialist in our area... We were lucky to have one, he sometimes frequents The Wall. We found out ours issue was a pressure issue and maybe wet steam. Although our gauges were reading  less than 1 psi let me tell you they were incorrect our system is running at 2-3lbs... just depends on what it feels like doing. So we our in the midst of correcting the issue and it's stuff I'm not will to do myself at this point. We have to clean the pig tail, skim the boiler, mess with the burner... Things like that...  I love our steam heat but I just want to tell it to be quiet I'm trying to sleep! My present comes the Tuesday before Christmas when it's our next service call...

    Just find someone who knows what they are doing... It will be worth the headache..
  • that's a Weil McLain boiler

    That's a Weil McLain boiler you have there... from the pictures, looks like you don't have the needed 28" of boiler riser before header... also this boiler have 1.5" skiming tap on the side.
  • Dave-o
    Dave-o Member Posts: 9
    pipe sizing

    RJB - what problems would be associated with the riser being less than 28"?  Is the skimming tap we have not sufficient?  Thanks.
  • Dave-o
    Dave-o Member Posts: 9
    main sizing

    Rod - the vent is attached to the return side of the 2" main and is about 8 ft from the boiler.  Is this the info you were looking for?

    I'll give "We Got Steam Heat" a read.

    Another point I wanted to bring up is that our brand new gorton radiator vents don't really drain properly.  This is one of the reasons I think we're dealing with wet steam.

    Thanks again for the feedback.
  • M Downey_2
    M Downey_2 Member Posts: 21
    Riser heigth

    Dave-O, what he's referring to is the fact that if the riser isn't the proper height, water can remained entrained in the steam, making for what the pro's refer to as "wet steam". The steam needs that riser height to allow the water droplets to drop out of the steam. That water which remains in the steam can cause a whole host of problems, including water hammer.  If you don't own a copy of  "The Lost Art of Steam Heat" I'd strongly recommend that you get a copy. It will help you understand your system and possible problems with it, much more.   
  • wet steam

    it may be a trick of perspective, but it looks like the hartford loop is at the wrong height, so if that were the case, i would suspect other piping mistakes, such as the height, and diameter of the riser.

    have a look on line at the manual for the boiler, and compare the piping requirements shown with what you have.

    definitely wrap some fiberglass insulation around the pipes, in such a way as to be removeable, for any corrective pipe work.

    get yourselves a christmas present of a good low-pressure gauge [gaugestore.com-0-3 psi] and put it on so you can keep the pressure down as low as it will go. if you have been really good all year, perhaps your secret santa will give you lots of gorton #2 vents, and a vaporstat [0-16 ounces]!!--nbc
  • I took another look

    I took another look at your pictures. Looks like the boiler is ethier EG 40/45/50 and your piping from boiler is reduced to 2" from the required 2.5" size. ( 3" would be better) The steam riser minimum pipe hieght is 24" from water table. I use the 28" for ' safety' factor.. Anything lower than 24" and undersized pipes will get you wet steam .... the skimming of the boiler will do better job of ' cleaning' the boiler than draining it. However, its the near pipings is causing the wet steam.. Do you still have the boiler manual? Its all there... better yet, get Dan's books.. " We got steam heat" and/or "The Lost Art of Steam Heating" from this site...
  • Pittsburgh Steam

    What I was asking is how long is the main from the boiler to the position of the vent and what is the diameter of the piping of the main to the vent. With these dimensions we can calculate the volume of air in the piping and then figure out the venting needed for that. You could just go with a Gorton #2 as that has a lot of venting capacity as it's pretty hard to over vent but easy to under vent.

    Radiators- Check your radiators and see that they slope towards the inlet pipe.  Use a carpenter's bubble level as measuring maybe a bit off if the floor has sagged. (This happens in older houses)  The slope doesn't have to be much, in fact to much can be detrimental. I use quarters ($.25) to initial adjust each radiator then go back with something more permanent. You just need enough slope to "encourage" the water to drain towards the inlet pipe. Also make sure the the valve on the pipe going into the radiator is fully open. These valves work fully open or fully closed ...never half way. Glad to hear you are getting "We Got Steam Heat" as all this in discussed in detail in it.  The book"The Lost Art of Steam Heating" was also mentioned. Thyis is a book you want to read after "We Got.." as it goes into residential steam systems in depth. They are available singlely or as a package deal. Here's a link to the package:  http://www.heatinghelp.com/products/Super-Deals/14/129/A-Steamy-Deal

    Boiler Piping: People are wondering about your riser length/height. The thing to do is to check the manufacturer's specifications. What is the model of your boiler?

    The "We Got Steam Heat" is going to answer a lot of your questions (with a much better explanation than I can give) which is one of the reasons I won't go into things like maintenance etc. here unless you have a specific question.  It probably best to just take a few things (venting, radiator slope)  at a time and see if they are in the accepted parameters.

    - Rod
  • Dave-o
    Dave-o Member Posts: 9

    Ok, so I found and read through the boiler manual (Weil-McClain, EG 50) and also took some measurements of the near-boiler piping.  The hartford loop looks like it's in the correct place, 2" below the water level.  However, the header is only 16" above the water level, the minimum distance being 24", and the manual also calls for 2 1/2" pipe for the riser and header just as RJB was saying. 

    My question is whether changing all of that piping would be a sure fire solution to the wet steam/whistling radiator problem.  I imagine it would be a good chunk of change to bring in a pro?

    Next steps:

    -replace the main vent.  I've got about 34 feet of 2" main piping between the boiler and the main vent, I'm assuming I should go with a Gorton #2 as suggested by Rod.

    -finish insulating pipes.  The plumbing supply place nearby sold me 36" sections for 2" pipe at $5.74 a piece... does that seem reasonable?  My one concern with insulating all pipes is that there is really no other source of heat down there.

    I'm slowly getting a handle on this steam heat thing.  Thanks again for all the feedback!
  • Never guaranteed

    that what you do will cure the problem, especially steam work.  You have to slowly fix the issues with the piping, controls, venting, insulation and eventually, if you persevere you will find the problem.

    That's a good price for insulation, especially if it's fiberglass; use none other.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hourTwo btu/ per sq ft for degree difference for a slab
  • David Nadle
    David Nadle Member Posts: 624

    I hope the insulation you got is more than 1/2" thick.
  • Venting

    I think in this case I'd make the least costly changes first.

    Main Vents -It would definitely benefit you having good main venting. A Gorton # 1 will theoretically vent 34 ft of 2 inch pipe in about 2 1/2 minutes. A Gorton # 2 in about 47 seconds.  Even 3 minutes is pretty fast so you could go with a Gorton #1  You might want to rig them on an "antler" and that way you can easily add more venting in the future if you think it's necessary. (see attached drawing)

    You didn't mention how the end of your steam main terminates: - down in the wet return? or to a F&T trap?

    Insulation- Obviously the more you have, the better insulated you are. However from a practical stand point the most economical vs benefit is 1 inch insulation.

    Boiler piping - This you can leave for last and see what the affect the other changes have. If you were going to make a change in the risers / header I'd use both exit ports in the boiler and go with a dropheader. In any case if possible I'd put this off till it was warmer in the spring.

    What size Gortons do you have on the radiators? What you might want to do is slow down the radiator venting as this would slow the velocity of the steam going into the radiators and maybe allow the excess water to drain back and not be carried along by the steam.

    - Rod
  • Dave-o
    Dave-o Member Posts: 9
    small fixes

    Rod - The main terminates into the wet return.  Also, thanks for the venting stats and suggestions about near-boiler piping and "antler" venting. 

    I think I'll stick with the smaller, less expensive fixes for now and will check in to let you guys know how things have developed.

    Thanks again,

  • HenryT
    HenryT Member Posts: 128

    Are there significant drawbacks in using fiberglass insulation that is 1/2" thick per the comments above? I recently bought insulation and the store only carried 1/2" thickness, i havent installed yet but if i need to upsize, please let me know.

    Rod, do you have that antler picture in a pdf?

  • David Nadle
    David Nadle Member Posts: 624
    One inch is better

    1/2 inch insulation isn't really adequate. The ASHRAE code for 2" steam mains is 1-1/2". After looking at the insulation characteristics I personally believe 1" insulation is the best bang for the buck.

    It's pretty much impossible  to find other than 1/2" in big box stores and local plumbing supply. I had a good experience with buyinsulationproducts.com, but they are close to me in NJ. If you can find a pipe insulation wholesaler locally you'll save a lot on shipping.
  • Unknown
    edited December 2009
    Antler PDF

    Hi Henry - I changed it into PDF for you. I'm afraid the drawing with the copying etc. is getting a bit "downgraded" - Rod
  • HenryT
    HenryT Member Posts: 128
    Thanks everyone.

  • wet steam from high pressure

    if you can get a vaporstat,to keep your pressure down to a few ounces, then i think that will reduce the terminal velocity at the end of each firing of the steam. you do need generous venting to make this work. and don't hesitate- insulate!

    in the spring you can think about a do-it-your-self-project on this, with some final help from a pro. even carrying the pipes down for the pro would help with the labor cost! --nbc
  • mel rowe
    mel rowe Member Posts: 324
    Similar experience

    Homeowner here with some experience that sounds very similar to some of your problems.  Have you calculated the velocity of steam leaving your boiler?  I never got rid of my wet steam related problems until I got the steam velocity way down from what I originally had with my oversized boiler.
  • Dave-o
    Dave-o Member Posts: 9
    steam velocity

    That sounds like a great approach to the problem.  How do you calculate and adjust steam velocity?
  • mchema
    mchema Member Posts: 37
    Finding someone is up to you...

    Like I said in a past post we were having very similar problems. Before you go repiping and getting into some money see if you can reduce the velocity of your steam. our piping isn't perfect around our boiler. Here are some things we did with working with our wonderful steam expert that helped get rid of our high pressure, wet steam monster...

    1) increased our main vents (4 Gorton #2 on each main total 8). We have about 20" mains.

    2) Washed the inside of the boiler out.  We didn't just skim. my guy found this method better. He washed and drained the boiler a few times.

    3) Cleaned out a plugged pig tail and fixed a broken pressurtrol.

    4) and the biggest most important thing was messing with the burner. He reduced how hot is was firing. So the pressure would not build up so high. It doesn't matter if you have a pressuretrol or a vapostat it's just going to cut your system off when the system pressure gets to a certin point. The trick is keeping the pressure low to non-existant and that's what he did.

    5)changed vents around the house

    The house heats much more evenly.

    It's a much happy place to be. No more hissing, spitting, squealing, banging,  no

    short cycling, just happy... Best money I have spent.  Some stuff I knew to do but some I didn't and  the stuff with the burner is something I would never messed with. There were too many varibles, overall.  Plus, my guy had all these awesome homemade tools that made the job that much easier.I can't say how happy I am  to have my steam guy by my side. But I mean it's up to you to find someone to help. I know I sleep better at night..
  • mike jones_2
    mike jones_2 Member Posts: 92
    steam velocity

    we own and manage buildings so we understand your approach.  however, dan's books makes the firing rate way beyond us, and i would check whether downfiring could hurt your efficiency and keep heat bills from being reduced. 

    i understand that an ideal flame and ideal combustion/emissions is the key to the firing rate and efficiency, and a temporary  solution might cost more in the long haul than correcting problems like piping when u have a chance.

    please confirm my advice with a pro if u pursue it
This discussion has been closed.